The present invention relates to a device for locking in position linear elements movable translationwise such as rods of cylinders and the like.
It is known that in the technical sector relating to the movement or manipulation of mechanical parts there exists the need to cause the displacement of said parts from one position to another by means of so-called linear movement units generally consisting of a slide which is movable, on fixed guide rods, by means of the thrusting/recall action of an actuator such as the rod of a cylinder or the shaft of a motor.
It is also known that, once the predefined position has been reached, said movement units must be locked in position by means of auxiliary devices which are associated with the actuating and/or guide means and must be able to withstand the stresses imparted to the part and hence to the actuator during the processing operations.
Said auxiliary locking devices are basically designed to produce a high frictional force which may be exerted on the rod of the actuator or on the guide rods of the slide, without causing at the same time undesirable displacements of the slide resulting from the sudden application of the locking force.
An example of the device known in the art is illustrated in EP 0,452,702.
Although fulfilling its intended functions, said device has limitations in that the constructional form described does not allow sufficiently high locking forces to be obtained on account of the fact that, if the value of the locking force were to be increased (something which would theoretically be possible), it would then be necessary to apply an unlocking force exerted by means of a jet of pressurised air which cannot be achieved using the normal devices available in work centres.
In addition to this, the known device has a structure which does not allow its dimensions to be kept within the volume of the body for connection of the actuating member.
The technical problem which is posed, therefore, is that of providing a device for locking linear actuating members such as cylinders and the like, which allows the overall dimensions to be kept within the said volume of the body for connection of the actuating member, but which, at the same time, allows positional locking forces to be exerted which are much higher than those currently possible with the known art, assuming the same force to be applied for unlocking.
Within the scope of this problem a further requirement is that said device should be easy and inexpensive to manufacture and assemble and should be easily applicable to actuating members of the known type.
These technical problems are solved according to the present invention by a device for locking in position linear elements movable translationwise, such as rods of cylinders and the like, which comprises an external body provided internally with a chamber housing elements for locking the rod, between which resilient means acting on the locking elements themselves are arranged, said chamber having formed inside it two opposing cylinders which are arranged on opposite sides of the rod and the pistons of which are designed to be arranged in a position for engagement with said locking elements so as to cause the movement towards one other and the consequent unlocking of the rod or, alternatively, in a position for disengagement from said locking elements so as to cause the movement away from each other and the consequent positioning of the latter in a position for locking of the rod.